1. Field of the Invention
The present invention relates to a method for manufacturing a semiconductor device, and more particularly, to a method for manufacturing a lightly doped drain (LDD) type MOS transistor, and either a bipolar transistor or a Schottky barrier diode (SBD) on the same substrate.
2. Description of the Related Art
In a fine structured MOS device, in order to avoid deterioration due to hot carriers, an LDD structure has been broadly used.
In a prior art method for manufacturing an LDD-structured MOS transistor and either a bipolar transistor or an SBD, a gate insulating layer is formed on a MOS transistor region and either a bipolar transistor or an SBD region. Then, a gate electrode is formed on the MOS transistor region. Then, an insulating layer is formed on the entire surface, and is etched back by a reactive ion etching (RIE) process to form a sidewall spacer only on a sidewall of the gate electrode. Then, in order to remove a part of either the bipolar transistor or SBD region damaged by the RIE process, a photoresist pattern is formed to cover the MOS transistor region, and the damaged part is etched by a chemical etching process using the photoresist pattern as a mask. This will be explained later in detail.
In the above-described prior art manufacturing method, however, an additional photolithography process for forming the photoresist pattern is required, thus increasing the manufacturing cost.